Method of making the joints of inner tubes



June 19, V1928.

- c. H. SEMPLE METHOD oE MAKING-THE JoINTsv oE INNER TUBES Patented June 19',

fof an automobile tire to illustrate my inven- UNITED STATES PATENT QFFICE.

CHARLES HERBERT SIEMPILE,y OF- YOUNGSTOWN, OHIO, ASSTGNOR, BY DIRECT'AND 'MESNE ASSIGNMENTS, T0 SEMPLETLEE IPROCESSES, NC., OF AKRON, OHIO,v A COIR- PORATON 0F DELAWARE.

METHOD 0F MAKING- THE JOINTS OF( INNER TUBES.

Application tiled December 23, 1924. Serial No. l757,691.4

My invention relatesv to the manufacture of inner tubes 4of automobile tires, or' other tubesthat are formed in a continuous ring. The object of the invention is tomake a joint between the two ends of atube quickly and accurately, said joint being strong and requiring but littlew'ork in preparing the ends of the tube tomake the j oint. j

In ,the accompanying drawings:

Fig. 1 is a sidevievw of sufficient of a tube tion, the parts being assembled prior to vulcanizing;

Fig. 2 is a sectional view on the line 2-2, Fig. 1;

Fig. 3 is a detached perspective view of the parts; and Fig. 4 is a perspective View) of la portion` of n'inner tube showing the com-A pleted joint.' l

Referring to the drawings, 1, 1 are the two ends of a rubber .inner tube that is used in pneumatic tires. The ends are cut oil' square, as shoiwn in Fig. 3, and a shield and guide 2, of. paper, is used` to align the two ends of the tube and to keep the unvul can-ized surfaces of the rubber from adhering withi-n the tube.. This guide-.is /preferably made of bulky soft paper, such as-blotting paper, or straw board, so thatitmay remain in the tube Without injury thereto during service. The guide istapered at one end, as

at 4, Fig. 3, to facilitate the bringing ofthe ends of the rubber tube accurately together l' for1 joining them, and both ends may be tapered, if found desirable. i

After the ends of-the tube-are passed over the guide, the ends are carefully washed with high testnaphtha or benzoLj-The two ends of the tube are brought into contact over the guide, which remains in the yclosed tube.

,The ends adhere immediately, makinga perfect union.

l Preferably the outer-'surface of the tube is then washed at the joint with naphtha,l or benzol, and a strip 3, of unvulcanized rubber, is wrapped around the joint, as, shown ,in Figs. 1 and-2,I One endof the strip 3 is 4beveledandv the other end overlaps thisbeveled portion, as illustrated in Fig. 2.

' When a. gas forming substance is used to evident as soon .as the mold isopened.

inflate the tube, a certain quantity of the substance is placed in the tube before the joint is made. The tube isjvulcanized in a suitable mold and the substance forming ajgasl inflates the tube so that it conforms to the mold. The result is a homogeneous rubber tube, which is reinforced at the joint, thereby overcoming liability of leakage at the4 location of the tube in the mold, and a suitable air connection 'is provided for in flating thetube while it is in the mold.

The paper guide 2 remains in the tube, as it does not`interferewith the inflation of the tube and, being of soft material, it' does not cut the tube but preferably is thin and flexible. and ofa material which will .not adhere to and thus add tothe thickness and stiffness of the wall.

The valvev reinforcements are preferably applied to the tubes prior to vulcanizing. After the tubes are taken from the vulcanizer, the valves are attached and the tubes vare ready`for packing and-delivery.

lllhile| the guide has been described as of paper, it may be made of `any suitable material, which'will separate the walls of a. tube. The guide may be placed first in one end of a tube, after which the end is Washed,

then the opposite end of-the tube may be washed and slipped over the tapered 'end of the'gu'ide. l'

, The process hereinbefore described-makes it unnecessaryto test a tube by inflation, as

any defect in the tube prevents it from expanding during'. the 'vulcanzation and is I claim The method of joining two'en'ds-ofrubbertubing which comprises sticking the vend portions of the tubing together and pressing them 1n a iiattened condition while preventing adhesion of theirinner walls by means -I of a thin and flexible, non-adhesive shieldy lying within and bridging the joint ofthe` .said end ortions.

LES HERBERT SEMPLE: 

